摘要: Spermatogenesis is critical for insect reproduction and the process is regulated by multiple genes. Glycosyltransferases have been shown to participate in the development of Drosophila melanogaster; however, their role in spermatogenesis is still unclear. In this study, we found that alpha 1,4-galactosyltransferase 1 (alpha 4GT1) was expressed at a significantly higher level in the testis than in the ovary of Drosophila. Importantly, the hatching rate was significantly decreased when alpha 4GT1 RNA interference (RNAi) males were crossed with w1118 females, with only a few mature sperm being present in the seminal vesicle of alpha 4GT1 RNAi flies. Immunofluorescence staining further revealed that the individualization complex (IC) in the testes from alpha 4GT1 RNAi flies was scattered and did not move synchronically, compared with the clustered IC observed in the control flies. Terminal deoxyribonucleotide transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay showed that apoptosis signals in the sperm bundles of alpha 4GT1 RNAi flies were significantly increased. Moreover, the expression of several individualization-related genes, such as Shrub, Obp44a and Hanabi, was significantly decreased, whereas the expression of several apoptosis-related genes, including Dronc and Drice, was significantly increased in the testes of alpha 4GT1 RNAi flies. Together, these results suggest that alpha 4GT1 may play dual roles in Drosophila spermatogenesis by regulating the sperm individualization process and maintaining the survival of sperm bundles.

摘要: Amid coevolutionary arms races between brood parasitic birds and their diverse host species, the formation of host-specific races, or gentes, has drawn significant research focus. Nevertheless, numerous questions about gentes evolutionary patterns persist. Here, we investigated the potential for gentes evolution across multiple common cuckoo (Cuculus canorus) populations parasitizing diverse host species in China. Using maternal (mitochondrial and W-linked DNA) and biparental (autosomal and Z-linked DNA) markers, we found consistent clustering of cuckoo gentes (rather than geographical populations) into distinct clades in matrilineal gene trees, indicating robust differentiation. In contrast, biparental markers indicated intermixing of all gentes, suggesting asymmetric gene flow regardless of geography. Unlike the mitonuclear discordance commonly resulting from incomplete lineage sorting, adaptive introgression, or demographic disparities, the observed pattern in brood parasitic cuckoos might reflect biased host preferences between sexes. We hereby present the Isolation by Gentes with Asymmetric Migration model. According to this model, the maternal line differentiation of the common cuckoo in China is potentially driven by host preferences in females, whereas males maintained the integrity of the cuckoo species through random mating. To achieve this, cuckoo males could perform flexible migration among gentes or engage in early copulation with females before reaching the breeding sites, allowing female cuckoos to store sperm from various gentes. Future studies collecting additional samples from diverse cuckoo gentes with overlapping distribution and investigating the migratory and copulation patterns of each sex would enhance our understanding of sex-biased differentiation among cuckoo populations in China. In the common cuckoo system in China, the matrilineal mitochondrial genes divided different cuckoo gentes into different clades, whereas the biparental autosomal markers showed all gentes intermixing together with asymmetric gene flow. Host preferences in females should explain maternal line differentiation, whereas the maintenance of cuckoo species relies on random mating from males, who may exhibit more flexible migration patterns or engage in early copulation with females. Isolation by Gentes with Asymmetric Migration appears to fit the diversifying system of the common cuckoo in China. image

摘要: The ricefield eel (Monopterus albus), a protogynous hermaphrodite, is an important aquaculture freshwater fish in China. Intensive studies have focused on the sex reversal of this species, but the underlying mechanisms remain elusive. We performed comparative transcriptome analysis for gonadal tissues of female, intersex, and male ricefield eels. The results suggest that temperature may play a role in inducing the sex reversal. Moreover, an epithelial-mesenchymal transition (EMT) gene signature was found, suggesting an involvement of germinal epithelium in contributing to gonadal transformation. Our in vitro and in vivo experiments show that thermal cues are sensed by thermosensors such as Trpv4 in the gonadal cells of ricefield eels, which can be transduced to the sex determination cascades. The epithelial cells of germinal epithelium can become Sertoli cells via an EMT. Our study provides new insights into the molecular mechanisms underlying the sex reversal of ricefield eels.

摘要: Aquaculture, as a major source of protein in the food industry, heavily relies on the introduction and farming of non-native species. Pikeperch, Sander lucioperca, an important fish in aquaculture, poses a threat to the survival of native species because it is a piscivore and has been introduced globally. To address this issue, we examined the niche dynamics of invasive populations by comparing the climatic niches of native and invasive populations of Pikeperch. Predictive models based on global occurrence data were used to assess the distribution areas of native and invasive populations, and the model results were converted into area measurements to estimate the potential invasion risk of pikeperch. The results show that invasive populations, especially those in Asia, occupy broader climatic niches. The main difference is that, compared to native-range populations, non-natives occupy warmer and more humid regions. These climatic differences have led to niche expansion by invasive populations, with invasive populations (particularly in Asia) showing a greater potential for invasion. we applied niche modeling to evaluate the potential invasion risks associated with introducing different geographic populations. Our models provide a scientific basis for managing aquaculture introductions, aiming to reduce invasion risks and minimiz both ecological and economic impacts.

摘要: The black rockfish (Sebastes schlegelii) is a marine species that is economically important in aquaculture, and the efficiency of its spermatogenesis is vital for its success in the aquaculture industry. Spermatogonia serve as the foundation of spermatogenesis in fish, possessing the ability for continuous self-renewal and progressive differentiation into mature spermatozoa. Moreover, Sertoli cells are crucial in modulating the proliferation and differentiation of spermatogonia. This study focused on the regulation of glycolysis by PLIN2a in Sertoli cells of the black rockfish and examined how the inhibition of glycolysis in these cells impacted the proliferation and differentiation processes of spermatogonia. We found that effective regulation of glycolysis was crucial for the metabolic activity and functional maintenance of Sertoli cells in black rockfish. Overexpression of plin2a in vitro enhanced glycolysis in Sertoli cells, whereas inhibition of glycolysis impaired their normal metabolic activity. In vivo inhibition of glycolysis in black rockfish testes lead to apoptosis of Sertoli cells and significantly suppressed the proliferation and differentiation of spermatogonia. These results underscore the essential role of glycolysis in the development and metabolic activity of Sertoli cells and highlight the critical regulatory role of glycolysis in determining the fate of spermatogonia. This study emphasizes the importance of regulating energy metabolism pathways, particularly glycolysis, in Sertoli cells to indirectly influence the development of spermatogonia, offering significant insights into the reproductive mechanisms of black rockfish and other teleost species.